Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains xii, 112 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 111-112).

The subgrade under a rail track, also known as the formation layer, performs a vital role in rail track stability. Its primary function is to withstand load imposed from rolling stock distributed through the track structure. Since common practice is to build rail track on the natural surface of the land, there is a considerable inherent variation. Problem soils such as expansive clays are common in Australia, which can suffer significant decreases in strength and stiffness when the soil moisture state is altered. A weak formation layer may experience plastic deformation and possibly shear failure leading to sever track geometry problems. Although there are many existing methods to remediate the causes of a loss in track geometry, most are expensive and also require track closure. / Thesis (MEng(CivilEngineering))--University of South Australia, 2006.

Thesis (Ph.D.)--University of Wollongong, 2006. / Typescript. Includes bibliographical references: leaf 190-212.

This thesis analyzed material on Mexican railroad development before 1876 to determine what principles underlay public action in this area. Only significant or recurring concessions concerning connecting Mexico City and Veracruz, transcontinental communication, and tying the United States and Mexico by rail were studied, since they provided the best means of tracing public action over an extended period of time.

In this thesis, the main objective is to identify the resilient deformation behaviour of rail trackbed especially in ballast and calculate the stress distribution. A purpose-designed three dimensional Finite Element railway trackbed model is presented in which linear elastic behaviour is assumed in all parts of the model. The study has also evaluated the effects of different variables including moving load magnitude, loading speed and stiffness of materials on stress conditions and deflections based. A comprehensive literature review on a wide background of railway trackbed has been carried out. Railway ballast specifications, deformation mechanisms, resilient and permanent deformation behaviour of granular material, introduction of fouling material and its influence on ballast behaviour are explained to provide the basis for trackbed analysis. Results show that a higher vertical displacement underneath the sleeper may occur when the loading speed is higher than 120km/h. Also, higher speed and Young’s modulus of ballast can result in higher damaging stresses. A stiffer subgrade can result in less rotation of sleeper. A significant effect of subgrade stiffness on stress paths and rotation of sleeper can only be found when Young’s modulus of subgrade is in a low level. Stiffer rail pad can lead ballast element get cracked more easily. Softer pad results in less damaging stresses. In addition, there is no obvious change of either the stress ratio or sleeper rotation as stiffness of the ballast increased.

Maintenance management decision-support systems are needed to help senior decision-makers and asset managers to better plan timely and efficient maintenance. Within the railway industry, several maintenance management decision-support systems have been developed. However, most these operate at project level where decisions are limited to short sections of track. Network level maintenance management systems enable future prediction of the condition of the railway network under different allocation of resources in a manner to provide acceptable levels of safety, reliability and cost. This project describes the development of a theoretical framework for the strategic assessment of network level railway maintenance funding and policy decisions. The model is designed to aid railway asset managers in planning medium to long-term maintenance investment requirements for the railway network. The model is based on stochastic processes which are capable of determining the effects of traffic, maintenance and climate on network condition under any budget scenario.

Ballasted track represents by far the most used infrastructure for railway transportation system, its main benefits being the relatively low construction costs, the maintainability, the relatively high damping capacity, noise absorption and high flexibility, the self-adjusting properties and high hydraulic conductivity. These are related to the structure of ballast layer as assembly as well as to particle properties. However, the unbound nature of ballast layer is also responsible for the reduction of geometric quality of the track, and therefore, its safety and ride comfort. The passage of trains causes cyclic movements of the unbound particles that result in permanent vertical and lateral deformations. For this track form, vertical settlement of granular layers and ballast particles degradation represent the major problems, affecting frequency of maintenance and track durability. In this context, reducing minor and major maintenance frequency while effectively using available resources by developing innovative technologies is a challenge for current and future railway research. After reviewing the most relevant existing solutions to improve ballasted track-bed behaviour and main factors affecting their performance, the aim of this research was to investigate the possibility of stabilising ballast with bitumen emulsion, as novel solution to slow down the loss in track quality associated with ballast settlement and particle degradation. In this regard, firstly the feasibility of the proposed alternative and main factors affecting its performance have been assessed through model-scale testing (small-scale Precision Unbound Material Analyser - PUMA). Results showed a good potential for this technology to reduce both the short-term and the long-term permanent deformation. It was also observed that bitumen stabilisation could modify mechanical properties due to the presence of a viscoelastic component (bitumen). The type of emulsion and its dosage played important roles in BSB properties: increasing the dosage of bitumen emulsion provided a better resistance to permanent deformation; increasing the viscosity of bitumen emulsion decreased the percentage of material lost, thereby providing improved stabilisation efficiency. Thus, depending on the field condition a specific bitumen emulsion could be designed to obtain the desired results in terms of BSB behaviour and stabilisation efficiency. At the same time, the use of harder bitumen for BSB seemed to improve the resistance to permanent deformation while polymer modification provided a more stable behaviour over time. Model-scale results provided important guidance on the influence of the factors analysed on the proposed technology. Nevertheless, to understand to what extent BSB could represent a solution to improve sustainability and performance of ballasted track-beds, findings had to be verified at full scale. Thus, full-scale box tests have been employed to assess how this technology could be effectively applied to existing ballasted tracks during maintenance operations and to investigate the practicability and maintainability of the presented technology. Results showed that bitumen stabilisation was more effective when applied at an early stage of ballast life (clean ballast), especially when coupled with tamping, providing a significant decrease to permanent deformation and to deformation rate (long-term behaviour). Nonetheless, in comparison with results obtained at model-scale, a slightly different behaviour of BSB in relation to unbound material was observed. Thus, with the aim of correlating previous model-scale PUMA and full-scale ballast box findings and evaluating long-term performance, full-scale PUMA testing was carried out. Results on clean ballast indicated that scale factor instead of the test type was the main factor controlling the effectiveness of Bitumen Stabilised Ballast (BSB) in terms of permanent deformation reduction. On the other hand, results obtained when using lower size aggregate confirmed that increasing the number of contact points increases also the influence of viscoelastic properties given by the bitumen, indicating that the use of different gradations combined with higher dosages (and types) of bitumen emulsions, could potentially modify full-scale track-bed mechanical properties. Key findings obtained from laboratory experiments, consistently showed evidence of the fact that bitumen stabilisation can reduce number of maintenance interventions due to geometry corrections and excessive particle degradation. In this regard, to estimate the environmental and economic impacts of BSB, a performance-based integrated model was developed to predict maintenance strategies of proposed technology in comparison to traditional ballast. This model, by combining the evolution of track irregularities with traffic and the level of contamination of ballast, allowed evaluation of the timing of corrective maintenance activities. Based on these, life-cycle environmental and economic costs of these alternatives have been carried out. Life Cycle Assessment (LCA) results showed that BSB is overall more sustainable than traditional ballasted track, only when considering also its impact on major maintenance operations. Sensitivity analysis carried out showed that BSB advantages are generally higher when the tolerance on the track quality level increases and with heavy traffic lines. LCCA results showed that BSB can provide important savings with respect to traditional ballasted track-bed. Sensitivity analysis showed that BSB would be more profitable for important and congested lines rather than peripheral ones. The influence of carbon conversion factor on results is relatively low while decreasing the discount rate corresponds to higher savings provided by the BSB. Overall, both LCA and LCCA results showed that BSB could offer a more sustainable solution from a life cycle perspective than traditional ballasted track-bed.

Thesis (Ph. D.)--Antioch University, 2006. / Title from PDF t.p. (viewed Mar. 29, 2007). Advisor: Jon F. Wergin. Keywords: narratives, portraiture, storytelling, charismatic leadership, underground railroad, voice and leadership. Includes bibliographical references (p. 173-177).

This record of study presents the findings of industry research projects performed during a one-year doctoral internship with the Austin Rail Group of HNTB Corporation. Four main internship objectives were established that address infrastructure problems related to the railroad industry and required the integration of engineering and financial analysis to develop effective project evaluation tools. Completion of the objectives resulted in: 1. Transformation of the Federal Railroad Administration methodology currently used to perform highway-railroad grade crossing analyses to a system of equations that can easily be used to evaluate regional rail infrastructure investments. Transportation engineering equations based on queuing theory were extended to new but equivalent formulations that accommodate unlimited, discrete train performance data from computer simulations of rail networks. 2. Application of risk assessment methods and railroad accident statistics to recommend a cost-effective alternative to legislative proposals to relocate hazardous materials transported by rail around metropolitan areas. A risk analysis model was developed to predict the risk of exposure from the release of a hazardous material following a train derailment so that changes in exposure achieved by alternative risk mitigation strategies could be observed. 3. A new method of measuring the susceptibility of railroads to financial distress following the catastrophic loss of a timber railroad bridge. Economic and finance principles were used to predict financial distress by determining of the number of revenue periods required to offset economic loss. 4. Demonstration of the use of financial market data in calculating the discount rate of public railroad companies for engineering analyses that involve negotiations with the public agencies. Surface Transportation Board rulings on the determination of a railroad?s cost of equity were applied to a comparative assessment of costs of capital for Class I railroads. A hypothetical example was used to demonstrate the interrelationship between engineering design strategies and their effects on the pricing of compensation to a railroad for right-of-way acquisition. These results, in fulfillment of the doctoral internship objectives, have provided HNTB with economic decision analysis tools and a series of conclusions used to provide recommendations to the Illinois, Missouri, and Texas Departments of Transportation, the Texas Legislature, and the railroad industry.

Thesis (M. Arch)--University of Pretoria, 2003. / Title from opening screen (viewed June 14, 2004). Summaries in English and Afrikaans. Includes bibliographical references.